The low frequency phonons dynamics in supercooled LiCl, 6H2O

Abstract

We report the results of a series of ultrasound,Brillouin scattering, and optical heterodyne detected transient grating experiments performed on a LiCl, 6 H 2 O solution from room temperature down to the vicinity of its liquid-glasstransition, T g ∼ 138 K . Down to T ∼ 215 K , the supercooled liquid has a behavior similar to what is expected for supercooled water: its zero frequency sound velocity, C 0 , continuously decreases while the corresponding infinite frequency velocity, C ∞ , sharply increases, reflecting the increasing importance of H bonding when temperature is lowered. Below 215 K, specific aspects of the solution, presumably related to the role of the Li + and Cl − ions, modify the thermal behavior of C 0 , while a β relaxation process also appears and couples to the sound propagation. The origin of those two effects is briefly discussed.